In recent years, various standards for recording a content on a storage medium such as an optical disk have been defined. As for DVDs, for example, the DVD Video standard (which will be referred to herein as “Video standard”) is defined as a recording format for a package medium to store a read-only content such as a movie thereon. Also, the DVD Video Recording standard (which will be referred to herein as “VR standard”) is defined as a recording format for recording a content in real time and for making it editable afterward. A general read-only DVD player can play back a content that was recorded so as to comply the Video standard but cannot play back a content that was recorded so as to comply with the VR standard.
Currently, read-only DVD players are still far more popular than any other type of DVD player/recorder. Accordingly, there is a lot of need to convert a content that was recorded so as to comply with the VR standard into a content compliant with the Video standard. For example, if video and audio, which were recorded on a storage medium with a camcorder so as to comply with the VR standard, should be handed to some acquaintance that owns a read-only player, the video and audio recorded needs to be converted into a content compliant with the Video standard.
In the prior art, such a format conversion process is carried out by decoding once a content that was recorded so as to comply with the VR standard, converting the content into a digital baseband signal, and then encoding the signal again such that the signal complies with the Video standard.
Alternatively, as in the process disclosed in Japanese Patent Application Laid-Open Publication No. 2002-150713, the format conversion process may also be carried out by recording in advance the physical storage locations of respective data of a given content on a storage medium and the time stamps thereof and by making reference to these pieces of information.
However, in the conventional format conversion process in which a content is once decoded and then re-encoded, the intervening re-encoding process step requires the same amount of time to get the conversion done as the amount of time it takes to record the original content. In addition, the image quality of the content easily deteriorates, which is a problem.
Also, in the format conversion process to perform by reference to the pre-recorded physical storage locations and time stamps of the data, the physical storage locations need to be recalculated during the format conversion, thus requiring a relatively long conversion time, too.